Apparatus for removing the solvent from solutions of resilient substances which are applied in considerable thickness to the single sheets of laminated glass for forming the nonsplintering intermediate layers



Feb. 28, 1939. KAMPFER 2,148,696 APPARATUS FOR REMOVING THE SOLVENT FROM SOLUTIONS OF RESILIENT SUBSTANCES WHICH ARE APPLIED IN CONSIDERABLE THICKNESS'TO THE SINGLE SHEETS 0F LAMINATED GLASS FOR FORMING THE NONSPLINTERING INTERMEDIATE LAYERS Filed Jan. 23, 1935 Patented Feb. 28, 1939 UNITED STATES PATENT OFFICE MEDIATE LAYERS.

Adolf Kampfer, Charlottenburg, Berlin, Germany Application January 23, 1935, Serial No. 3,152 In Germany January 23, 1934 7 Claims.

This invention relates to a method of removing the solvents from solutions of resilient substances which are applied in considerable thickness to the single sheets of laminated glass for the purpose of forming non-splintering intermediate layers,the layers being subjected in an enclosed space, for such time, until the solvent has evaporated, to the action of an atmosphere charged with vapours of the solvent in order to keep the surfaces of the layers soft, and thus permit of the escape of rising bubbles of gas or vapour. It is the object of this .invention to develop this process to an additional extent, so that there is ensured a mpre thorough removal of the solvent from the layers than has-hitherto been possible, and so that at the same time danger of deliquescence or other variations in the position or form of the layers is eliminated.

Since the amount of air enclosed within the space'is invariable, and at a constant temperature is capable of absorbing merely a given quantity of the solvent vapours up to complete saturation, a thorough removal of the solvent from the layers is only possible if the quantity of solvent contained in the layers is less than the power of absorption of the air. If it is greater, a proportion of the solvent must necessarily remain in the layers. An additional drawback associated with the old method consists in the fact that with increasing saturation of the air enclosed within the space the evaporation of the- I solvent is retarded, so that such a process requires a very long time, inasmuch asthe point at which the solvent has been completely expelled or at which the air has been saturated with vapours of the solvent is extremely diflicult to determine.

In consequence the period of action of the solvent atmosphere is also very long, so that there is always the danger that the layers will be softened from the outside up to the point of deliquescence.

The invention consists in replacing the air above the layers, after its saturation with solvent vapours, or immediately prior .thereto,*by fresh air at the same temperature. This replacement of the saturated air by fresh air may be repeated as many times as needed until the solvent expelled from the layers has been completely removed. In lieu of this measure, or additional thereto, an increase in the powers of assimilation or absorption of the air above the 'layer'for solvent vapours may be accomplished by a steady or a stepby-step increase in the temperature of the air.

If both measures-repeated substitution of the 55 practically saturated air by unsaturated air. and

steady or step-by-step increase in the temperature of the .air to be charged with the solvent vapours-are combined, the increase in pressure caused by the higher temperature may be utilized for automatically controlling the optimum de-; 5 gree of saturation in each stage, in such fashion that a pressure valve or the like, either directly or indirectly at a certain admissible pressure, allows a part of the mixture of vapour and air to escape from the enclosed space, and causes the replacementthereof by fresh air at the same temperature. In this way the evaporation of the solvent may be greatly accelerated, and the action of the solvent atmosphere on the layers so regulated as regards duration and intensity that in each case an excessive softening of the layers from the outside isavoided. -By repeated substitution of the practically saturated air above the layer and repeated step-by-step increase in the temperature of the air to be saturated complete expulsion of the solvent contained in the layers may be quite readily accomplished in a comparatively short time. Once the'solvent has been completely removed a deformation or even deliquescence of the layers is unable to take place, irrespective of the length of time for which the layers remain under the action of the last-mentioned temperature.

The solvent may be recovered in the known fashion by condensation from the mixture of air and solvent vapours discharged. The layers treated according to this process maybe covered in immediate fashion with a cover sheet.

An apparatus suitable for carrying out the new process is illustrated diagrammatically by way of example in the drawing.

Fig. 1 shows the apparatus partly in vertical longitudinal section and partly in elevation.

Fig. 2 is a section along the line 2-2 in Fig. 1;

Fig. 3 is a detailed sectional view of the'coupled valves controlling fluid flow through the inlet and outlet pipes of the chambers.

A container l is divided by horizontal partitions 2 into a plurality of superimposed channellike chambers 3, which serve to receive the sheets of glass 4 with the layers 5 from which the solvent is to be removed. Each chamber 3 is capable of being closed tightly at the two ends by doors or flaps 6a and 6b or in other fashion, and contains a heating device, such as a serpentine tube 1 fed with steam. The partitions 2 forming the bottoms of the single chambers may be covered with sheets of glass for the purpose ofobtaining an exactly flat form. Runners may also be provided in recesses or cavities in these bottom for 55 the sheets or glass to be treated in the chambers.

In front of the container I, i. e., opposite to the inlet openings in the ends of the chambers: 3 closedby the flapsfid, there is arranged a horizontal table 9, which is adjustable insuch fashion as regards its elevated position by suitable means, as for instance, the collars 9 and set screws 9 that it may be moved successively into the planes of the floors of the several chambers. Above the table there is provided means I0, which serves for application of the plastic solution to the single sheets of glass, and which is carried by the I table 9 through the medium of a support H, and

is accordingly. adjustable in height together with the table. The sheets of glass to be furnished with the plastic layers are placed upon the table 9, then conducted below the application device l0, and finally passed into the particular chamber 3 which may have been selected. Various means may be employed for conveying the sheets of glass; for example, the table 9 may be furnished with a large number of operated runners situated in close proximity to each other. In the particular form of embodiment shown there is employed for conveying the sheets of glass a web |2 of paper or other cheap-quality material,

which is drawn over the table through the particular chamber 3 to be charged. This web is withdrawn from a permanently mounted-supply roll l4, and so deflected by means of a roller l5 -mounted on the table that upon each adjustopen out into a common pipe 22, by means of ment of the table it moves along the surface of the table. -After a chamber has been charged with the assistance of this web |2 with the desired number of coated sheets of glass the part of the web |2 located within the chamber is cut ofl, so that the chamber may be tightly closed. Immediately the treatment of the sheets of glass introduced into the chamber has been completed, 1. e., immediately the plastic coatings on the sheets of glass have been freed of their solvents,

the closure flap SD or the like at the outlet end of the chamber is opened, in order to be able to withdraw the sheets of glass from the chamber with the assistance of the portion of the web of paper remaining in the chamber. If desired the finally treated sheets of glass may be discharged 'upon an endless conveying belt II, which is adjustable asregards height.

Each chamber 3 is furnished with an outlet pipe 2Q for the mixture composed of the solvent vapours and the air contained in the chamber. This outlet pipe 2|! contains a choke valve 2|, which is not illustrated in detail, and-which opens automaticallyupon the pressure of the mixture of air and vapour contained in the chamber rising to a certain predetermined degree. This tlet. valve may naturally also'be arranged in such fashion that it is operable by hand or is controlled periodically by a suitable operating device. The outlets 20 ofall chambers which the discharged mixture ofsolution saturated air is conducted to a condenser 28, in which the solvent may be recovered. Parallel to the outlets 20 there. extends into each'chamber I apipe 25 serving for the supply of fresh air. This pipe 25 extends into a portion of the chamber remote from the pipe 20 so. that when fresh air enters through the pipe 25, it will force out air within the chamber 3 into the outletpipe 20.

All pipes 25 extend from header 26 of an air pump 21, which is driven by an electro-motor 28.

ing device 29, by which the fresh air to be intromanner that the two valves 2| and 30 may be opened and closed simultaneously. To the two valves 2| and 30 belonging to each chamber 3 there is associated a pair of contacts 32 controlling the circuit of the electro-motor 28, in such fashion that upon the common opening movement of the two valves the motor circuit is completed as for instance by the yoke M, and together therewith the air pump 21 set into operation. If, therefore, the outlet valve 2| for the mixture of air and vapour pertaining to any particular chamber is opened, there occurs simultaneously the opening of the air inlet valve MB and the supply of pre-heated air to the chamber.

The heating element 1 of each chamber is furnished outside of the container with a manually operable or automatically acting device 35, shown as a valve for regulating the heating effect. With the assistance of this regulating device the temperaturein the ,interior of each chamber may be increased gradually or step-bystep, in such a manner that complete saturation of the air in the c amber with the solvent vapours escaping fro the plastic layers of the sheets of glass is never quite. reached. This effect is amplified bythe fact that when a certain pressure in the interior of the chamber has been attained, or at different pressure or temperature stages, a part of the, mixture of air and vapour I is discharged from the chamber and replaced by fresh, pre -heated air.

What I claim as new and desire to secure by Letters Patent isz- 1 Means for evaporating solventsfrom a layer of material to which the solvent has been applied, including a chamber having movable closures at its opposite ends, the chamber having a floor, a table disposed in alinement with the door of the chamber closely adjacent thereto, a roll-supporting a sheet of fibrous material, the fibrous material being drawn over said table and constituting a support for the article to be treated, the fibrous material constituting means whereby the article after the layer of material and. solvent has been applied thereto may be drawn into said chamber and the closures closed, heating including. a plurality of superposed chambers,

each chamber having'movable closures at its ends, each chamber having heating meansdisposed above'the floor of the chamber. and each chamber having means whereby solvent saturated air may be withdrawn therefrom and fresh air "introduced thereinto, a table adjustable into alinement with the floor of any one of said chamhers and closely adjacent thereto, and a sheet of fibrous material adapted to be drawn over the" face of thetable-and support the article tq be treated and to be drawn into said chamber and thus convey the article from the table into the chamber. 3. In an apparatus of the character described.

a chamber having means for opening or closing it, heating means within the'chamber, a saturated into the chamber and a connection between the valves effecting simultaneous opening of the valves when the pressure within the chamber increases beyond a predetermined amount, an air pump and heater connected to the fresh air inlet pipe, an electric motor for the air pump, and means carried by the valves acting to close a circult through the air pump motor when the valves are opened by a rise of pressure within the chamber.

4. In a mechanism of the character described, a

chamber having means whereby it may be closed or opened, a-heater extending into the chamber and having means for regulating heattherein, an outlet pipe leading from the chamber and adapted to conduct solvent saturated air from within the chamber, a pressure operated valve normally closing said outlet pipe but opening automatically upon the rise of pressure within the chamber beyond a predetermined amount, a fresh air inlet pipe opening into the chamber, a normally closed valve therein, and a connection between the first named "valve and the last named valve causing the opening of the second named valve upon the opening of the first named valve."

5. An apparatus for preventing the deliques-- maticaily cutting 01! the admission of fresh medium to the interior of the chamber and the discharge of solvent-laden medium when the pressure within the chamber has become reduced to a predetermined degree. 7

6. An apparatus for preventing the deliques- -cence of a layer of resilient substance applied to a sheet of glass, including incombination a chamber adapted to be tightly closed and to contain a solution absorbent atmosphere, heating means in. the chamber, a vapor outlet leading from the chamber, an inlet valve controlling an inlet leading into the chamber fromv a source of absorptive medium, fa pressure actuated valve affected by the pressure within the chamber and opening the vapor outlet when the pressure within the cham ber has reached a predetermined degree, and an operativeconnection between said pressure operated outlet valve and the'inlet valve to cause the opening and closing of the inlet valve coincldently with the opening and closing of the outlet valve.

7. An apparatus for preventing the deliquescence of a layer of resilient substance applied to'a. sheet of glass, including .in combination achamber adapted to be tightly closed and to contain a solution absorbent atmosphere, heating means in the chamber, means operative to positively with draw the gaseous medium from within said chamber and having a conductive connection with the chamber, a pressure operated valve normally shutting off passage of the gaseous medium between the chamber and the withdrawing means, an inlet valve controlling the inlet of fresh medium into said chamber, and an operative connection between said inlet valve and the outlet valve constructed and arranged to cause the opening or closing of the inlet valve vcoincidently with the-opening or closing of the outlet valve.

ADOLF 

